Question

détente means
increased openness.
restructuring.
reform.
a relaxing of tensions.

Explanation:

Détente is a French term. In the context of international relations, it specifically refers to a period where there is a reduction or relaxation of political tensions between countries. "Increased openness" is more related to concepts like glasnost. "Restructuring" is perestroika. "Reform" is a more general term. Détente's key meaning is about easing tensions.

Answer:

a relaxing of tensions.